Antibiotic Susceptibility Profiles of Escherichia coli Isolated from Bird Nests Indicate that they Can Serve as Reservoirs for Antibiotic-resistant Bacterial Strains in the Environment

Abstract

The emergence and dissemination of antibiotic-resistant bacterial strains in environmental niches is a growing public health concern with significant implications for human health. Wild birds can potentially transmit antibiotic-resistant bacteria across ecosystems, and their frequent nesting near human habitats heightens the risk of human exposure. This study evaluated the antibiotic susceptibility profiles of Escherichia coli strains isolated from bird nests collected from various locations in Akoko Southwest, Ondo State, Nigeria. E. coli was isolated from the collected bird nests by inoculation on Eosin Methylene Blue (EMB) agar, and the identity of the isolates was confirmed based on their cultural characteristics, cellular morphology, and selected biochemical reactions. The phenotypic susceptibility of the E. coli isolates to selected antibiotics was assessed using the disc diffusion assay. E. coli was isolated from 53.13% of the collected nests, with concentrations ranging from 2.0x10¹ to 2.8x10² CFU/g. The E. coli strains isolated from the bird nests in this study exhibited resistance to several of the antibiotics tested, with resistance predominantly observed for tetracycline (41.18%) and amoxicillin-clavulanate (47.06%). Results from this study demonstrated the significance of bird nests as reservoirs for antibiotic-resistant bacterial strains in the environment.